Method of actuating a master and printing therefrom while on a printing drum

ABSTRACT

The heat absorbing text of a printing master is placed in contact with a dye coating on a sheet and irradiated so that portions of the dye coating in contact with the heat absorbing text melt and adhere to the heat absorbing text while the remainder of the dye coating remains on the sheet when the same is pulled off the master.

United States Patent Inventor Gerhard Ritzerfeld Franzensbader Strasse21, Berlin- Grunewald, Germany Appll No. 619,495

Filed Feb. 3, 1967 Patented Jan. 5, 1971 Priority Feb. 8, 1966 GermanyNo. R42589 METHOD OF ACTUATING A MASTER AND PRINTING THEREFROM WHILE ONA PRINTING DRUM 10 Claims, 9 Drawing Figs.

U.S. Cl 101/471, 250/65.1 Int. Cl 841m 5/20, GOln 21/34 Field of Search101/468,

References Cited UNITED STATES PATENTS Russell Miller Raczynski et a1.Raczynski et a1. Roshkind Beatty et a1.. Ritzerfeld Russell et alLimburger Primary Examiner-William B. Penn Attorney-Michael S. StrikerABSTRACT: The heat absorbing text of a printing master is placed incontact with a dye coating on a sheet and irradiated so that portions ofthe dye coating in contact with the heat absorbing text melt and adhereto the heat absorbing text while the remainder of the dye coatingremains on the sheet when the same is pulled off the master.

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METHOD OF ACTUATING A MASTER AND PRINTING THEREFROM WHILE ON A PRINTINGDRUM BACKGROUND OF THE INVENTION imprints. The number of copies whichcan be obtained depends on the type of hectographic master and ismaximal 400 copies. Thereupon, a new master has to be written.

It has been proposed to regenerate the master by means of a hectographicinking sheet which is subjected to differentiated heat radiation. Thisrequires a special thermographic apparatus for producing adifferentiated infrared radiation. The

use of an additional apparatus is uneconomical and time consuming sothat a certain given amount of orders or invoices cannot be handled inthe required time.

Independently of the above disadvantages, organizational duplicatingsystems require the use of an existent master in different successiveprinting operations, each of which requires a newly written additionalmaster, for example for part deliveries. If the main master is used fora great number of copies, and the additional masters only for smallernumbers of copies, a substantial color difference between the parts ofthe copies made by the main master and theparts of the copies made bythe additional masters occurs which results in a poor appearance of thecopies if purple duplicating ink is'used, and which is intolerable ifblack hectographic inking sheets are used. However, particularly the useof black inking sheets which can produce only a limited number ofcopies, is particu- Iarly necessary for producing a deep black imprintof all parts of the text on all copies. The use of hectographic masterswith duplicating ink brings about soiling of the fingers of the typistmaking the master and of the machine operator during the duplication andand during the regeneration of the master. Also, the use of hectographicmasters in high speed printers in modern data processing machines causesdifficulties due to the soiling of the high speed printer and of theperson operating the same. It has been recently suggested to use forwriting or printing of masters soot containing inks which do not containa hectographic dye.

' SUMMARY OF'TI-IE INVENTION It is one object of the invention toovercome the disadvantages of the prior art regarding making andactivating duplicating masters, and to provide an arrangement whichpermits the making, regenerating and activating of hectographicduplicating masters of high quality without soiling the machine or itsoperator.

Another object of the invention is to provide a method for making orregenerating a hectographic'duplicating master in a short time, and byusing the duplicating machine. I

With these objects in view, the present invention is concemed with theactivation of a master whose text is radiation to the text. When thesheet is removed with the remaining coating, the radiation absorbingtext'of the master is covered with a dye coating adapted to betransferred to copy sheets moistened with alcohol. 1

The dye used in the coating is preferably a triphenylmethane dyeembedded in a bonding'substance, and the radiation is preferably eitherinfrared radiation, or high frequency waves producing sufficient energyto melt the dye coating only where the radiation is absorbed by the textof the master which is in contact with the dye coating.

When the melted dye has hardened again and is securely attached to thetext of the master, the coated sheet is either manually or mechanicallypulled off the master.

It is possible to transfer a coating and to separate thesheet from amaster during 1 revolution, or during 2 successive revolutions of aduplicating drum or other carrier.

In one embodiment of the invention, the coated sheet is a band-shapedweb which is taken off a first reel and wound up on a second reel. Thesection between the reels is pressed against the master and irradiated.The wind-up reel is driven from the rotary carrier of the master througha friction roller so that the web is moved substantially in synchronismwith the revolving master.

In another embodiment of the invention, the coated sheet is superimposedon the master, and both sheets are held tight on the periphery of thecarrier or duplicating drum.

The novel features which are considered as characteristic for theinvention are set forth'in particular in the appended claims. Theinvention itself, however, both as to its constructionand its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary sectional viewillustrating a duplicating machine provided with the apparatus of theinvention in a position of rest;

FIG. 2 is a fragmentary sectional view of the apparatus illustratinganother operational position at the start of the transfer of dye to themaster;

FIG. 3 is a fragmentary sectional view illustrating the apparatus inanother operational position shortly before removal of the coated sheetfrom the master;

FIG. 4 is a fragmentary sectional view illustrating an operationalposition of the master in which the coated sheet is pulled off themaster;

FIG. 5 is a fragmentary sectional view illustrating a modifiedconstruction of the pressure means in a position of rest of theduplicating machine, parts illustrated in FIGS. 1 to 4 being omitted inFIG. 5 for the sake of simplicity;

FIG. 6 is a fragmentary sectional view taken on lines D-E in FIG. 3; 7

FIG. 7 is a fragmentary sectional view illustrating another embodimentof the invention with a detachable unit which can be used in an existentduplicating machine;

FIG. 8 is a fragmentary sectional view illustrating a duplicatingmachine provided with the unit shown in FIG. 7, wherein the pressuremeans are modified; and

FIG. 9 is a fragmentary sectional view taken on lines I-H in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,a duplicating drum 1 is mounted on a rotary shaft 2 and has a i firstholding means for clamping a master 4 to the periphery of drum 1. Themaster has on its outside a carbon mirror script text 6, and on itsinside a positive legible outline 5 of the text. A sheet 9 has an innercoating 10 consisting of a dye such as a triphenylmethane dye in abonding base, and is held in a second holding means 7. In theoperational position of FIG. 1, the apparatus is in a position of rest,but when rotation of the duplicating drum 1 is started, the coated sheet9, 10 is superimposed on the outside of master 4. A manually operablerod 11 has a cutout 14 which can be hooked onto a correspondingarresting part of a bracket 15 by which rod 11 is guided. When rod 11 ismoved to the right, lever 16 turns about pivot 17 in the direction ofthe arrow A, and shifts, while lever 18 turns about pivot 19, link 20 inthe direction of the arrow B. Toggle levers 21 and 22 are displacedalong the path defined by lever arm 23 turning about pivot 19 so thatthe support 24 with pressure rollers 12 and 13 and the source ofradiation 25, move away from duplicating drum 1 and assume aninoperative position,

wheel 129 from theduplicating drum.

Parts 126 to 135 constitute a l-revolution clutch effecting stopping ofduplicating drum 1 after a-singlerevolution.

A motor, not shown, drives through a gear. 126, the gear- 127 which isfreely rotatableon shaft 2 and fixedly connected with a ratchet wheell29an'd a'flange 142. When latch 132 is held 1 by spring 134 in theposition of FIG. 1', a pawlv130 is arrested and cannot turn about itspivot 135 under theactionof spring 131 toa position engaging the ratchetwheel and coupling the same through pivot l35gto the duplicating drum 1so that the same is arrested in the position of FIG. 1.

-When the operator releases latch-1'32 by turning the same about pivot133,-spring 131 movespawl 130 toitsrcoupling position engaging ratchetwheel 129, and theduplicating drum starts its rotation in clockwisedirection of the arrow until pawl l30vengages latch 132 after Irevolution ofthe drum, and is separated from the ratchetwheel sothat thedrum stops. The

duplicating drum is part of a' conventional duplicating machine whichincludes a counter pressure roller'la, a pair. of

sheets are supplied.

In the operational'position of FIG. 2, the duplicatingdrum has turnedso-far-that the pressure roller 13 engages'theout- 1 side of 'the coatedsheet 9 and presses the same with the ink coating .10 againstrthe carbontext .6 of the master-which has radiation absorbing properties. Counterpressure roller in also holds the coatedsheet '10 superimposed on'themaster. The source of radiation 25, which mayproduce infraredradiation .or a highfrequency radiation, irradiates the leading-portionsof the coated sheet 9 and of the master 4 in theposition-of 'FIG. 2,sincetsupport 24 is held in its operative position by the lever systemdue to the'fact that rod 11 is in its operative position. I

During further rotation of the duplicating drum, the ap- ,paratus.assumes the position of FIG. 3' so that consecutive pairs of sectionsof the coated sheet and of the master 4 are irradiated.ln the positionof FIG. 4, the superimposed sheets "havepassed beyond'the pressureroller means 12, 13, and the duplicating drum approaches its-position ofrest in which pawl 13.0twill engage latch 132 and separate the drivenratchet 'Referring again to FIG. 2, it is not necessary toenergize thesource of radiation when the duplicating drum is in the positions ofFIG. 1 or'FlG. 4, in which the coated sheet and master are not locatedin the region of the source ofradiation 25.

As shown in FIG. 2, a part circular member 76a is secured to the endface of drum 1 and .is engagedby slide contactl76 which is connectedwitha switch 75 in the circuit,.not shown, of the radiation source 25.Radiation source .-25'is only ener gized when slide contact 76 isengaged by the part circular .inember 76a. which is disposed to closethe circuit of the radiation source shortly before the same is passed bythe leading edges of sheets 9 and 4, and to open the same shortly afterthe trailing edges of the sheet have passed the radiation source,

The circuit of the radiation source is closed such a time before theleading ,parts of the superimposed sheets 9 and 4 reach the region 'ofradiation source 25, that the same has warmed -up and is fully heatedwhen acting on the superimposed sheets.

The pressure rollers 12 and 13 smooth sheets 4 and 9 and hold the samein contact with each other and with the periphery of the duplicatingdrum. The carbon text 6 on master 4 is irradiated through the dyecoating 10 of sheet.9 and is heated so that the portions of the dyecoating abutting the heat absorbing carbon text are heated to such atempera- Y ture as to melt and adhere to the heat absorbing carbon textof the master sheet, while the remainder of the dye coating, which didnot receive a heat reflex from the carbon text remains attached to sheet9.

'FIGSJ3 and 6 showth'e apparatusin axpositionin-which the source ofiradiation-is :passedbysections of the superimposed sheets.to-successively irradiate the entire- 'coatedl sheet "and master sheet.The-leading.edgesofccoated sheet 9 and master :sheet4 and theholding'rneans7 -and.3..approaeh a%giippen'33. Holding means 7- of thercoatedsheetllt) :is opened, and: the released leadingpart ofcoated -sheeti:10 is being'pushed-byQan :ejector 1 member away from: the.:peripheral surface amine duplicatingdrum and intofthe regionofgripperf33. 1

"As best seen in "FIG. 6, two ;-releasing members #94 are mounted .on. ashaft =93 andcooperate-withFholding' means '7. During rotation of theduplicatingidrum, cam 95 which is mounted on a pivot '30 actsz'onta'roller 97of -cam=92 onshaft -93 to effect opening of holding means 7 attheproper moment. A' manually. operatedrod" 9.1, guided-in :a' bracket96,. is connected-with.carn 95and'is'shiftable to'a position in whichits cutout 91a .is hooked into bracket 96" so that cam 95 is retractedto an inoperative. position in which itcannotactuate camfollower means-92, 97:to;open=holding means7. hile holding; means *7 is "thus closedan'd inoperative, I duplicating operations may becarried out.lf cam 95would'remainopera- :tiveduring duplicating operations, holding means 7,which is not used during such operation, would "be unnecessarily openedandclosed. When holding means -7 has. been opened in the position ofFIG. 3,:the.;roller 27-of a camfollower 28 one shaft .29 isengaged by-.acarnr32awhich-ismountedon-a pivot 3l,'and turns cam follower lever 28inithe'direction of the arrowiCi-sothat shaft.-29-tums in itsbearing'simthe end walls of theduplicating -.drum 7.2 andrdisplacesejector 126 which pushes .the leading part: of the .co'atedsheetQ-away.from the .duplicating'drum and into the region o'fsgripp'er v33. Cam-32is connected with a manually; operable.rod 99, and can be turned by-thesameto an inoperative .zposition spaced from roller 27 so that ejector26 is notactuated duringa-duplicating operation. g After ejector 26has-,perfomied its function, cam follower roller 97-is movedbyztheduplicating drum beyond cam 95, so

that aspiring-connected withcamfollower 92-retnmsmember 94 to itsoriginal position-.closingholding means 7. g

The :rotary movement of duplicating=drum -l carries the released leading.portionof a coated sheet 9 into'gripperl33 'which has a fixed jaw and-amovable jaw which is turnable an;

' :shaft.35 which'rigidly supports'thefixedjaw. The movable :jaw

ispart of .an angular lever34loadedby a spring 36and carrying a.camsfollowerroller38 .cooperatingwitha ro'tarycam 37 secured to a shaft42 .driven'througha gear train 41, 40, .39 from'the duplicating'drum.Cam.37"hassuch-a shape 'that the gripper is open until the leadingedgeof thecoated sheet 9is moved by the duplicating drum between the twojaws of gripper 33.-Thereupon,'a "higher portion of 'cam 37 engages camfollower'roller38 andc'loses'the gripper so that the leading edge of thecoated sheet 9is clamped,iasshown in FIG. -4.

During :further turning movement of duplicating drum '1, roller.27movesbeyond .cam32 and permits the-return'of-lever arm 28 by aspring'to itsoriginal'position in which ejectors.26 are retractedinto the interior-oftheduplicating drum whose peripheral wallhas cutoutsfor the'passage'ofejectors 26.

Referring nowto FIG. 4, gripper 33 gradually. pulls thecoated-sheet'9off master 4 which'continues to move with the duplicatingdrum l. Since the coat 10 adheres to the master,

the coated sheet 9 forms a loop. The portion of coating 10 ad- When thecoated sheet 9 is completely separated from.

master 4, roller 38 is moved by the action of spring 36 tothe lowerportion of cam 37, and the gripper opens and relases the coated sheet 9,which is either manually removed from the machine or guided into areceptacle, not shown.

Cam 37 is mounted on shaft 42shiftable in axral direction to" aninoperative position spaced from cam follower roller-38 of gripper 33 sothat duplicating operations can'be carried out without operation ofgripper33. 1 v- FIG. 5 corresponds to FIGS. 1 and 6 as far as theduplicating machine, the gripper, the ejector, and the second holdingmeans 3 and 7 are concerned, but the radiation and pressure unit ismodified. The source of radiation 25 is mounted on a support 45 which isoperated from a manually operable rod 14. The source of radiation islocated within a glass cylinder 44 covered with a soft transparent layer43. The tubular member 44, 43 abuts the peripheral surface of theduplicating drum 1, and the superimposed sheets 9 and 4 along a firstline. Two spaced lines of the tubular member 43, 44 are engaged by apair of rollers 46, 47 mounted on support 45. Consequently, the tubulartransparent member 43', 44 is rotatably supported at three points, androtates due to the frictional engagement with the peripheral surface ofthe duplicating drum 1 or with sheet 9. The pressure of the tubularmember 43, 44 on the superimposed sheets smoothes the same and holds thedye coating in contact with the heat absorbing carbon text on theoutside of master 4. The pressure rollers used in the embodiment of FIG.1 are replaced by the transparent tubular pressure tube 44, 43.

The removal of the coated sheet 9 from the master has been describedwith reference to FIG. 4 to be carried out at the end of the samerevolution during which the coated sheet is irradiated, and portions ofits coating transferred to the heat absorbing text of master 4. However,it is possible irradiate and master during a first revolution, and toopen holding means 7, operate ejector 26, and close gripper 33 during asecond revolution of the duplicating drum.

FIGS. 7, 8 and 9 illustrate a modified embodiment of the invention inwhich the irradiating and pressure unit can be attached to and detachedfrom a standardduplicating machine. The duplicating drum 1 has only oneholding means for the master sheet 4, and the coated sheet is notmounted on the duplicating drum, but is a band-shaped web 79 whose dyecoating 82 is located opposite the peripheral surface of the duplicatingdrum and the carbon text 6 on the outside of master 4. A support member88, 136 can be operated to move between the inoperative position shownin FIG; 7 to an operative position in which a drive roller 86frictionally engages the peripheral surface of duplicating drum 1 and isrotated by the same. A pulley 83 is connected by slide clutch 100 to thedrive roller 86 and drives through a belt 84 a pulley 81 on a shaft 76rotating the takeup reel of the band-shaped coated web 79. The coatedweb 79 is unwound from a takeoff reel on shaft 80 which is braked by abar brake 112, biased by spring 113 and mounted on a pivot 111. Duringduplicating operations, when the coated web must not engage theduplicating drum, the support 88, with cam 136 is in the retractedposition shown in FIG. 7, and the drive roller 86 is separated from theduplicating drum so that the same can perform the usual duplicatingoperations producing imprints of the master on copy sheets.

In order to hold the device in this inoperative position, the support88, 136 is shifted by a linkage connected with the manually operated rod102.

When the rod 102 is shifted to the right and cutout 10l is hooked ontobracket 103, lever 115 turns in the direction of the arrow F about pivot116 and shifts, while turning lever 117 about pivot 118, latch 119 inthe direction of the arrow G. Due to this motion, toggle levers 120,121, which are controlled by guide lever 122 turning about pivot 118,move the source of radiation 25, the pressure rollers 12, 13, the driveroller 86, and the support 87 of the radiation source by means ofsupport 88 and 136 to the inoperative position spaced from theduplicating drum. Support 88, 136 is mounted on support 87 of the sourceof radiation, which also supports pressure rollers l2 and 13 forrotation.

The housing 90 on which the above-described parts are mounted hasbrackets 137, 138, 139 and 140 which are mounted in slots in thesidewalls of the duplicating machine. When the dyeing of the master 4 isrequired, cam 109 causes movement of support 88, 136 to the operativeposition in the proximity of the duplicating drum 1 when the leadingpart of the master approaches the region of the source of radiation 25.Spring 124 holds the cam follower roller in this position of rod 102 onthe lower portion of cam 109. A switch 75 has a slide contact 76a whichcooperates with an arcuate contact 76a on the end walls of theduplicating drum as described with reference to FIG. 2 so that thesource of radiation 25 is energized shortly before the leading part ofthe master approaches the source of radiation, and is deenergized whenthe trailing portion of the master has passed beyond the same.

As mentioned above, the source of radiation may produce infraredradiation, or a high frequency ion radiator may be used. The transfer ofdye from the coated sheet 79 to the text 6 on master 4 may be effectedduring 1 or several revolutions of the duplicating drum. The brake 112prevents inertia rotation of the takeoff reel which may move the webinto contact with the drum when the unit is moved to the inoperativeposition of FIG. 7 in which the takeup reel is not driven by drive wheel86 since the same is spaced from the drum.

If the counter pressure roller la, transporting rollers 1b and themoistening means 10 are omitted, the apparatus is limited to the dyeingof master sheets, and is not used for duplicating operations so thatdrum 1 constitutes a carrier for the master 1 and is not used as aduplicating drum.

FIG. 8 illustrates a modified arrangement which corresponds to theconstruction described with reference to FIG. 7, but has instead ofpressure rollers 12 and 13, a tubular transparent pressure memberconsisting of a glass tube 44 with a thin transparent cover 43, andenveloping the source of radiation, as described with reference to FIG.5.

The method of the invention permits the use of a conventionalduplicating machine for providing the text of the master with a layer ofdye, or activating a master, the dye of whose text is exhausted byimprints on many copy sheets since the remaining text permits theadhering of dye from the coated sheet, as explained above.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofprinting machines differing from the types described above.

While the invention has been illustrated and described as embodied in aduplicating machine provided with a unit for transferring a dye from acoated sheet to the carbon text of a master, it is not intended to belimited to the details shown, since various modifications and structuralchanges may be made without departing in any way from the spirit of thepresent invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

I claim:

1. A method of activating a master and printing with the same,comprising attaching to a printing drum a master having on one sideradiation absorbing means forming a reverse text so that said one sidefaces outward in a position ready for printing; placing at least asection of a sheet having on one side a coating of a transferable dyewith said one side in contact with said one side of said master;rotating said printing drum with said master; moving said sheet inunison with said master so that pairs of sections of said sheet andmaster are successively superimposed; irradiating said superimposedsections and said coating between the same whereby radiation absorbed bysaid radiation absorbing means heats the portions of said coating whichare in contact with said radiation absorbing means so that said heatedportions of said coating adhere to said radiation absorbing means ofsaid master; removing said sheet from said master while the same remainsattached to said rotating printing drum so that said adhering heatedportions remain on said radiation absorbing means whereby the reversetext formed by said heat absorbing means of said master is activatedwhile the coating remaining on said sheet is removed with the same;placing a plurality of copy sheets successively in contact with saidmaster during successive revolutions, respectively, of said printingdrum with said master so I rotation of said printing drum; anddeenergizing said source in a second selected angular position of saidprinting drum when 'the trailing superimposed sections of said sheet andmaster have passed said source during further rotation of said printingdrum.

3. The method of claim 1 wherein said sheet is superimposed on saidmaster so that all said heat absorbing means are in contact with saidcoating.

4. The method of claim 1 wherein said sheet is irradiated from the otherside of said sheet with infrared radiation to melt said portions of saidcoating; and wherein said dye of said coating is a triphenylmethane dyeembedded in a bonding substance.

5. The method of claim 1 wherein successive pairs of sections of saidsheet and master are irradiated from the outer other side of said sheetduring rotation of said printing drum.

6. The method of claim 1 wherein said sheet is a bandshaped web; andcomprising successively unwinding sections of said web from takeoffmeans; placing each unwound section on said master; and winding up eachunwound section after irradiation so that each wound-up section isremoved with the remaining coating from said master.

7. The method of claim 1 wherein said sheet is manually removed fromsaid master after irradiation.

8. A method of activating a master and printing with the same,comprising attaching to a printing drum a master having on one sideradiation absorbing means forming a reverse text so that said one sidefaces outward in a position ready for printing; placing at least asection of a sheet having on one side a coating of a transferable dyewith said one side-in contact with said one side of said master;rotating said printing drum with said master; moving said sheet inunison with'said master so that pairs of sections of said sheet andmaster are successively superimposed; irradiating said superimposedsections and said coating between the same whereby radiation absorbed bysaid radiation absorbing means heatsthe portions of said coating whichare in contact with said radiation absorbing means so that said heatedportions of said coating adhere to said radiation absorbing means ofsaid master; gripping and holding the leading edge of said sheet duringrotation of said printing drum with said master so that said sheet ispeeled off said master while the same remains attached to said rotatingprinting drum so that said adhering heated portions remain on saidradiation absorbing means. whereby the reverse text formed by said heatabsorbing means of said master is ac,- tivated while the coatingremaining on said sheet is removed with the same; placing a-plurality ofcopysheetssuccessively in contact with said master during successiverevolutions, respectively, of said printing drum with said master sothat legible imprints of said reverse consisting of said coating aremade on a plurality of copy sheets before said master is againactivated.

9. The method of claim 8 wherein said sheet and said master areirradiated during a first revolution of said printing drum; andincluding gripping and holdingof the leading edge. of said sheet duringa second revolution of said printing drum so that said sheet with saidremaining coating is removed from said master.

10. The method of claim 8 wherein said sheet and said said master.

1. A method of activating a master and printing with the same,comprising attaching to a printing drum a master having on one sideradiation absorbing means forming a reverse text so that said one sidefaces outward in a position ready for printing; placing at least asection of a sheet having on one side a coating of a transferable dyewith said one side in contact with said one side of said master;rotating said printing drum with said master; moving said sheet inunison with said master so that pairs of sections of said sheet andmaster are successively superimposed; irradiating said superimposedsections and said coating between the same whereby radiation absorbed bysaid radiation absorbing means heats the portions of said coating whichare in contact with said radiation absorbing means so that said heatedportions of said coating adhere to said radiation absorbing means ofsaid master; removing said sheet from said master while the same remainsattached to said rotating printing drum so that said adhering heatedportions remain on said radiation absorbing means whereby the reversetext formed by said heat absorbing means of said master is activatedwhile the coating remaining on said sheet is removed with the same;placing a plurality of copy sheets successively in contact with saidmaster during successive revolutions, respectively, of said printingdrum with said master so that legible imprints of said reverse textconsisting of said coating are made on a plurality of copy sheets beforesaid master is again activated.
 2. The method of claim 1 wherein saidsuperimposed sections are irradiated by a source of radiation;comprising energizing said source of radiation in a first selectedangular position of said printing drum when the leading superimposedsections of said sheet and master approach said source during rotationof said printing drum; and deenergizing said source in a second selectedangular position of said printing drum when the trailing superimposedsections of said sheet and master have passed said source during furtherrotation of said printing drum.
 3. The method of claim 1 wherein saidsheet is superimposed on said master so that all said heat absorbingmeans are in contact with said coating.
 4. The method of claim 1 whereinsaid sheet is irradiated from the other side of said sheet with infraredradiation to melt said portions of said coating; and wherein said dye ofsaid coating is a triphenylmethane dye embedded in a bonding substance.5. The method of claim 1 wherein successive pairs of sections of saidsheet and master are irradiAted from the outer other side of said sheetduring rotation of said printing drum.
 6. The method of claim 1 whereinsaid sheet is a band-shaped web; and comprising successively unwindingsections of said web from takeoff means; placing each unwound section onsaid master; and winding up each unwound section after irradiation sothat each wound-up section is removed with the remaining coating fromsaid master.
 7. The method of claim 1 wherein said sheet is manuallyremoved from said master after irradiation.
 8. A method of activating amaster and printing with the same, comprising attaching to a printingdrum a master having on one side radiation absorbing means forming areverse text so that said one side faces outward in a position ready forprinting; placing at least a section of a sheet having on one side acoating of a transferable dye with said one side in contact with saidone side of said master; rotating said printing drum with said master;moving said sheet in unison with said master so that pairs of sectionsof said sheet and master are successively superimposed; irradiating saidsuperimposed sections and said coating between the same wherebyradiation absorbed by said radiation absorbing means heats the portionsof said coating which are in contact with said radiation absorbing meansso that said heated portions of said coating adhere to said radiationabsorbing means of said master; gripping and holding the leading edge ofsaid sheet during rotation of said printing drum with said master sothat said sheet is peeled off said master while the same remainsattached to said rotating printing drum so that said adhering heatedportions remain on said radiation absorbing means whereby the reversetext formed by said heat absorbing means of said master is activatedwhile the coating remaining on said sheet is removed with the same;placing a plurality of copy sheets successively in contact with saidmaster during successive revolutions, respectively, of said printingdrum with said master so that legible imprints of said reverseconsisting of said coating are made on a plurality of copy sheets beforesaid master is again activated.
 9. The method of claim 8 wherein saidsheet and said master are irradiated during a first revolution of saidprinting drum; and including gripping and holding of the leading edge ofsaid sheet during a second revolution of said printing drum so that saidsheet with said remaining coating is removed from said master.
 10. Themethod of claim 8 wherein said sheet and said master are irradiatedduring a revolution of said printing drum; and including gripping andholding of the leading edge of said sheet during said revolution of saidprinting drum so that said sheet with said remaining coating is removedfrom said master.